She's been married nearly 70 years—she says this relationship red flag is the most telling: 'It’s painful'

The Engelmans have also seen from the outside what a bad relationship can look like. Their No. 1 red flag that says a relationship might not last is "criticism which is not constructive but meant to devastate and demean someone," says Rosalyn.This criticism can be made about many things."If someone is serving something and you criticize the way it looks, tastes and you know someone has spent hours doing this," she says, "or you say the table doesn't look good, or how about that other shirt that goes better with those pants?" Any hurtful comment made for the sake of hurting someone is a red flag.

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